welcome to the site Fusiion.
what are you trying to do here? is there a reason for using two amps? those resistors are not for the led's and they should remain the same. you should test the output and use a resistor that matches your led array (you can use more than one led, the pic is just an example). In theory, I would say the output and supply is equal to the amp's supply, or 5V
I have personally never used this set up, I generally mod the xbox so someone correct me if I am wrong.